The former president of the Maldives says he expects to be jailed after being ousted from his post earlier in the week in what he says was a coup at gunpoint.

A criminal court in the capital Male has now issued arrest warrants for ousted president Mohamed Nasheed and his former defence minister, but the charges against them were unclear, a senior official of Mr Nasheed's Maldivian Democratic Party (MDP) said.

"An arrest warrant has been issued for him and his former defence minister," MDP official Adam Manik said.

"We have no idea [what the charges are]."

Police said on state TV on Wednesday night that protests led by Mr Nasheed after his ousting were "an act of terrorism".

Mr Nasheed told reporters at his house in Male on Thursday that he expected to be in jail on Friday.

About 200 supporters stood under umbrellas in the pouring rain outside as he spoke.

"The home minister has pledged [I will be] the first former president to spend all my life in jail," said Mr Nasheed, who was relaxed and smiling and showed no signs of his reported beating on Wednesday.

"I hope the international community will take note of what is happening in the Maldives."

He said he hoped the international community would act quickly as "the facts on the ground are that tomorrow I will be in jail".

He said he had sent his wife and one of his two daughters to Sri Lanka for their own safety as violence worsens.

MDP officials say police and soldiers are on their way to arrest Mr Nasheed, who earlier met with a Commonwealth delegation in the luxury Indian Ocean resort islands to mediate in the political crisis that followed his resignation on Tuesday.

The tumult this week is far away from the thousands of upmarket tourists who visit the islands each week. Up to 1 million people visit the Maldives each year, and tourism forms a major chunk of its GDP.

Mr Nasheed was injured on Wednesday when police broke up protests against his ouster, and there was no immediate word on his whereabouts.

He said earlier he was forced to quit at gunpoint.

"There were guns all around me and they told me they wouldn't hesitate to use them if I didn't resign," he told a news conference.

Vice president Mohamed Waheed Hassan Manik was installed as president and has said he will form a government of national unity.

Protests against Mr Nasheed's government started after he ordered the military to arrest the criminal court chief justice, saying he was blocking multi-million dollar corruption and human rights cases against the allies of Maumoon Abdul Gayoom, president for 30 years until he was replaced by Mr Nasheed.

The Progressive Party of the Maldives, led by Mr Gayoom, said in a statement it was appalled by Mr Nasheed's "desperate attempts at insurgency to return to power barely 24 hours after his resignation".

"Nasheed must know that militancy and chaos do little to repair his tarnished image," it said.

The United States says it now recognises the new government of president Mohamed Waheed as legitimate.

However, Britain's High Commissioner to Sri Lanka and the Maldives, John Rankin, says he is concerned for Mr Nasheed.

"We are aware of reports of an arrest warrant issued for president Nasheed," Mr Rankin said.

"We are concerned that no harm comes to him. If it did, it would be a matter of serious concern for us and the international community."